Errors with Neuromag 306 raw data

Lauri Parkkonen lauri at NEURO.HUT.FI
Fri Feb 3 11:45:49 CET 2006

Hello Robert and Jon

>> The first error was: ??? Undefined function or variable  'iscontinuous'.
>> ...
>> To work around this, I edited fieldtrip-20060131/private/
>> trialfun_neuromag.m to replace iscontinuous on line 13 with 1.  The
>> edited line reads  "trigger = read_fcdc_data(cfg.datafile, hdr, 1,
>> nsamples, chanindx, 1);"
> I think that fif files are continuous by default, but I am not sure.
> It matters for filtering and artifact detection, since reading over a
> discontinuous trial boundary would result in a weird jump in the signal.

Yes, the "raw data" fif files are continuous over trials, i.e., there is
no "epoch mode", however, one fif file can hold several data segments.
For example, two different experimental conditions can be recorded in
the same file as separate segments; the boundary between the segments is
of course a discontinuity. The MEX function "rawdata" returns the string
'skip' as status when a segment boundary is encountered in a fif file. I
have added some more checking to read_fcdc_data so that these boundaries
are not silently ignored.

Robert: I could incorporate my changes to your most recent version since
my read_fcdc_data is very old.

With the best regards,

Lauri Parkkonen
Brain Research Unit, Low Temperature Laboratory
Helsinki University of Technology
Otakaari 3 A, 02150 ESPOO, FINLAND
tel: +358-9-4512965
fax: +358-9-4512969
mailto:lauri at

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